The present invention relates in general to energy absorbers and, more specifically, to an impact energy absorber for absorbing the energy of a force applied to a panel of an automotive vehicle.
In motor vehicles, particularly, in passenger cars, energy absorbers are secured in a space between an interior trim member and a structural member of a vehicle body. For example, energy absorbers may be secured between a pillar, a roof side rail, a header and an interior trim material, such as a pillar garnish or a roof lining. The energy absorbers are designed to absorb a load, such as a head impact of a vehicle occupant, to the interior trim member. The energy absorber deforms to absorb energy from the impact load that is applied in a direction from the interior trim member and to translate the load to the structural member.
One type of energy absorber is described in U.S. Pat. No. 5,680,886 to Ohtsuka. The energy absorber described in the ""886 patent is a tube formed of a metal foil core member and sheets of kraft paper that are applied to opposite side surfaces of the foil core member. The core member and the sheets on the opposite side surfaces of the core member are corrugated so that ridges and grooves alternate in a direction of an axis of the pipe.
The pipe disclosed in the ""886 patent is formed into a quadrangular shape. The load applied to a quadrangular energy absorber is supported between side walls of the energy absorber that extend between the interior trim member and the structural member. The stiffness of a quadrangular shaped energy absorber depends on the distance between the side walls. As a result, the further the side walls are spaced apart, the less stiff the energy absorber is. The stiffness of the quadrangular energy absorber may be tuned by changing the spacing between the side walls, changing the corner radii of the tube, changing the material the tube is made from, or changing the corrugations of the tube.
There is a need for an improved energy absorber tube that includes one or more supports, between side segments, that support a portion of the applied load and allow the stiffness of the tube to be changed without changing the overall size, the material, or the corrugations of the tube.
The present disclosure concerns an impact energy absorber. The disclosed impact energy absorber is a flexible pipe or tube made from a metal foil provided with substantially sequential spiral-shaped concavities and convexes about a periphery of the pipe along a length of the pipe. The energy absorbing pipe defines a cross section that includes a flat segment for attachment to an inner or outer body panel, first and second side segments that extend from the flat segment and a segment that connects the first and second side segments. The first and second side segments act as supports for an applied load. The segment that connects the first and side segments is shaped to define a third support between the first and second side segments that support a portion of an applied load.
In one embodiment, the segment that connects the first and second side segments includes a negative draft that acts as a third support for an applied load. In one embodiment, the segment that connects the first and second side segments includes a concavity that acts as a third support for an applied load. In one embodiment, the energy absorber has a substantially kidney-D shaped cross section.
In one embodiment, the energy absorber is used in an automotive body panel assembly. The body panel assembly includes an outer panel and an inner panel positioned to form a space between the inner panel and the outer panel. The impact energy absorber is positioned in the space between the inner panel and the outer panel. The flat surface of the energy absorber is secured to the outer panel or the inner panel.
The energy absorber functions to absorb a load applied to the inner panel. A first portion of the load applied to the inner panel is supported by the first and second segments to absorb a portion of the applied load. A second portion of the applied load is supported by the third support of the energy absorber tube that is in between the first and second side segments.
Additional features of the invention will become apparent and a fuller understanding will be obtained by reading the following detailed description in connection with the accompanying drawings.